AD - AS model - case study PDF

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A case study in the AD-AS model lesson. Hope it helps...

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CASE STUDY: THE GREAT DEPRESSION AND WORLD WAR II At the beginning of this chapter, we established three key facts about economic fluctuations by looking at data since 1965. Let’s now take a longer look at U.S. economic history. Two episodes jump out as being particularly significant: the large drop in real GDP in the early 1930s and the large increase in real GDP in the early 1940s. Both of these events are attributable to shifts in aggregate demand. The economic calamity of the early 1930s is called the Great Depression, and it is by far the largest economic downturn in U.S. history. Real GDP fell by 27 percent from 1929 to 1933, and unemployment rose from 3 percent to 25 percent. At the same time, the price level fell by 22 percent over these 4 years. Many other countries experienced similar declines in output and prices during this period. Economic historians continue to debate the causes of the Great Depression, but most explanations center on a large decline in aggregate demand. What caused aggregate demand to contract? Here is where the disagreement arises. Many economists place primary blame on the decline in the money supply: From 1929 to 1933, the money supply fell by 28 percent. As you may recall from our discussion of the monetary system, this decline in the money supply was due to problems in the banking system. As households withdrew their money from financially shaky banks and bankers became more cautious and started holding greater reserves, the process of money creation under fractional-reserve banking went into reverse. The Fed, meanwhile, failed to offset this fall in the money multiplier with expansionary openmarket operations. As a result, the money supply declined. Many economists blame the Fed’s failure to act for the Great Depression’s severity. Other economists have suggested alternative reasons for the collapse in aggregate demand. For example, stock prices fell about 90 percent during this period, depressing household wealth and thereby consumer spending. In addition, the banking problems may have prevented some firms from obtaining the financing they wanted for investment projects, and this would have depressed investment spending. Of course, all of these forces may have acted together to contract aggregate demand during the Great Depression. The second significant episode in Figure 9—the economic boom of the early 1940s—is easier to explain. The obvious cause of this event was World War II. As the United States entered the war overseas, the federal government had to devote more resources to the military. Government purchases of goods and services increased almost fivefold from 1939 to 1944. This huge expansion in aggregate demand almost doubled the economy’s production of goods and services and led to a 20 percent increase in the price level (although widespread government price controls limited the rise in prices). Unemployment fell from 17 percent in 1939 to about 1 percent in 1944—the lowest level in U.S. history. •

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OIL AND THE ECONOMY

Some of the largest economic fluctuations in the U.S. economy since 1970 have originated in the oil fields of the Middle East. Crude oil is a key input into the production of many goods and services, and much of the world’s oil comes from Saudi Arabia, Kuwait, and other Middle Eastern countries. When some event (usually political in origin) reduces the supply of crude oil flowing from this region, the price of oil rises around the world. U.S. firms that make gasoline, tires, and many other products experience rising costs, and they find it less profitable to supply their output of goods and services at any given price level. The result is a leftward shift in the aggregate-supply curve, which in turn leads to stagflation. The first episode of this sort occurred in the mid-1970s. The countries with large oil reserves got together as members of OPEC, the Organization of Petroleum Exporting Countries. OPEC is a cartel—a group of sellers that attempts to thwart competition and reduce production to raise prices. And indeed, oil prices rose substantially. From 1973 to 1975, oil approximately doubled in price. Oil- importing countries around the world experienced simultaneous inflation and recession. The U.S. inflation rate as measured by the CPI exceeded 10 percent for the first time in decades. Unemployment rose from 4.9 percent in 1973 to 8.5 per- cent in 1975. Almost the same thing happened a few years later. In the late 1970s, the OPEC countries again restricted the supply of oil to raise the price. From 1978 to 1981, the price of oil more than doubled. Once again, the result was stagflation. Inflation, which had subsided somewhat after the first OPEC event, again rose above 10 percent per year. But because the Fed was not willing to accommodate such a large rise in inflation, a recession was soon to follow. Unemployment rose from about 6 percent in 1978 and 1979 to about 10 percent a few years later. The world market for oil can also be a source of favorable shifts in aggregate supply. In 1986, squabbling broke out among members of OPEC. Member countries reneged on their agreements to restrict oil production. In the world market for crude oil, prices fell by about half. This fall in oil prices reduced costs to U.S. firms, which now found it more profitable to supply goods and services at any given price level. As a result, the aggregate-supply curve shifted to the right. The U.S. economy experienced the opposite of stagflation: Output grew rapidly, unemployment fell, and the inflation rate reached its lowest level in many years. In recent years, the world market for oil has not been as important a source of economic fluctuations. Part of the reason is that OPEC has been less effective as a cartel: Adjusted for inflation, the price of oil has never again reached the record levels set in the early 1980s. In addition, conservation efforts and changes in technology have reduced the economy’s dependence on oil. The amount of oil used to produce a unit of real GDP has 2

declined about 40 percent since the OPEC shocks of the 1970s. As a result, the economic impact of any change in oil prices is smaller today than it was in the past. Nonetheless, it would be premature to conclude that the United States no longer needs to worry about oil prices. Political troubles in the Middle East or greater cooperation among the members of OPEC could always send oil prices higher. And indeed, during the Iraq war, the price of crude oil did rise signifi- cantly. If the rise in oil prices were ever large enough, the macroeconomic result would most likely resemble the stagflation of the 1970s. • QUESTIONS FOR REVIEW 1. Name two macroeconomic variables that decline when the economy goes into a recession. Name one macroeconomic variable that rises during a recession. 2. Draw a diagram with aggregate demand, short- run aggregate supply, and long-run aggregate supply. Be careful to label the axes correctly. 3. List and explain the three reasons the aggregate- demand curve is downward sloping. 4. Explain why the long-run aggregate-supply curve is vertical. 5. List and explain the three theories for why the short-run aggregate-supply curve is upward sloping. 6. What might shift the aggregate-demand curve to the left? Use the model of aggregate demand and aggregate supply to trace through the short-run and long-run effects of such a shift on output and the price level. 7. What might shift the aggregate-supply curve to the left? Use the model of aggregate demand and aggregate supply to trace through the short-run and long-run effects of such a shift on output and the price level. PROBLEMS AND APPLICATIONS 1. Suppose that the economy is in a long-run equilibrium. a. Draw a diagram to illustrate the state of the economy. Be sure to show aggregate demand, short-run aggregate supply, and long-run aggregate supply. b. Now suppose that a stock-market crash causes aggregate demand to fall. Use your diagram to show what happens to output and the price level in the short run. What happens to the unemployment rate? c. Use the sticky-wage theory of aggregate supply to explain what will happen to output and the price level in the long run (assuming there is no change in policy). What role does the expected price level play in this adjustment? Be sure to illustrate your analysis in a graph.

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2. Explain whether each of the following events will increase, decrease, or have no effect on long-run aggregate supply. a. The United States experiences a wave of immigration. b. Congress raises the minimum wage to $10 per hour. c. Intel invents a new and more powerful computer chip. d. A severe hurricane damages factories along the East Coast. 3. Suppose an economy is in long-run equilibrium. a. Use the model of aggregate demand and aggregate supply to illustrate the initial equilibrium (call it point A). Be sure to include both short-run and long-run aggregate supply. b. The central bank raises the money supply by 5 percent. Use your diagram to show what happens to output and the price level as the economy moves from the initial to the new short-run equilibrium (call it point B). c. Now show the new long-run equilibrium (call it point C). What causes the economy to move from point B to point C? d. According to the sticky-wage theory of aggre- gate supply, how do nominal wages at point A compare to nominal wages at point B? How do nominal wages at point A compare to nominal wages at point C? e. According to the sticky-wage theory of aggregate supply, how do real wages at point A compare to real wages at point B? How do real wages at point A compare to real wages at point C? f. Judging by the impact of the money supply on nominal and real wages, is this analysis consistent with the proposition that money has real effects in the short run but is neutral in the long run? 4. In 1939, the US economy not yet fully recovered from the Great Depression, President Roosevelt proclaimed that Thanksgiving would fall a week earlier than usual so that the shopping period before Christmas would be longer. Explain what President Roosevelt might have been trying to achieve, using the model of aggregate demand and aggregate supply. 5. Suppose that the economy is currently in a recession. If policymakers take no action, how will the economy change over time? Explain in words and using an aggregatedemand/aggregate- supply diagram. 6. For each of the following events, explain the short-run and long-run effects on output and the price level, assuming policymakers take no action. a. The stock market declines sharply, reducing consumers’ wealth. b. The federal government increases spending on national defense. c. A technological improvement raises productivity. d. A recession overseas causes foreigners to buy fewer U.S. goods.

7. Suppose that firms become very optimistic about future business conditions and invest heavily in new capital equipment. a. Draw an aggregate-demand/aggregate-supply diagram to show the short-run effect of this optimism on the economy. Label the new levels of prices and real output. Explain in words why the aggregate quantity of output supplied changes.

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b. Now use the diagram from part (a) to show the new long-run equilibrium of the economy. (For now, assume there is no change in the long-run aggregate-supply curve.) Explain in words why the aggregate quantity of out- put demanded changes between the short run and the long run. c. How might the investment boom affect the long-run aggregate-supply curve? Explain. 8. Explain whether each of the following events shifts the short-run aggregate-supply curve, the aggregate-demand curve, both, or neither. For each event that does shift a curve, draw a diagram to illustrate the effect on the economy. a. Households decide to save a larger share of their income. b. Florida orange groves suffer a prolonged period of below-freezing temperatures. c. Increased job opportunities overseas cause many people to leave the country.

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